How to Calculate Concrete
Slab: Volume = Length (ft) × Width (ft) × Depth (in) ÷ 12 ÷ 27 = cubic yards
Column: Volume = π × (Diameter/2)² × Height ÷ 1728 ÷ 27 = cubic yards
Tips for Ordering Concrete
- Always add 10% extra for waste, spillage, and uneven surfaces
- Ready-mix trucks typically carry 8-10 cubic yards
- For small projects (< 1 yard), bags may be more economical
- Standard concrete weighs about 4,050 lbs per cubic yard
- Set time is typically 24-48 hours; full cure takes 28 days
Frequently Asked Questions
How many bags of concrete for 1 cubic yard? About 45 bags of 80 lb mix, 60 bags of 60 lb mix, or 90 bags of 40 lb mix.
What thickness for a driveway? Standard is 4 inches. Heavy-duty driveways should be 5-6 inches.